The present invention concerns bottle receiving means comprising transport means for transporting bottles, identifying means with a data processing unit for identifying and accepting bottles having given shapes, and recording means for recording the accepted bottles. The identifying means comprise a chiefly or mainly stationary illuminating means for illuminating the bottle, a detector for examining the bottle, and a conveyor for moving the bottle past the detector.
Bottle receiving means are known in the prior art, based on use of a laser beam, in which the shape of the bottle is examined with the aid of a laser beam reflected on the bottle with the aid of a rotating mirror. The information on the shape of a bottle is obtained with the aid of a detector consisting of optic fibers. Accepted bottles are identified in a processing unit, to which the information on the respective bottle under examination is conducted in the form of electrical signals in order to compare the shape information of the bottle under examination with equivalent data of acceptable bottle shapes provided in a file. Information on accepted bottles is conducted to a recording unit which records the number of accepted bottles and, for instance, their type and/or possibly the amount of money to be refunded for the bottles on a voucher which may be debited by a checkout attendant.
Bottle receiving means are particularly well usable in the bottle returning departments of major foodstuff stores and department stores, and stores for selling beer.
The bottle receiving means of the prior art is susceptible to malfunctions, inasmuch as the laser is a sensitive component and the rotating mirror requires extremely exact aligning. This makes the manufacturing of the bottle receiving means rather difficult, and results in high cost of the same. Furthermore, natural wear of the means causes need for servicing, since the various parts of the means require special precision for faultless operation.
Bottle receiving means have been disclosed in Finnish Patent No. 71892, comprising transport apparatus for transporting bottles, identifying means for identifying and accepting bottles having given shapes, and recording means for recording accepted bottles. The identifying means comprise a principally or mainly stationary illuminating means for illuminating the bottle, a detector for examining the bottle, and a conveyor for moving the bottle past the detector. The detector contains a lineal camera arranged to examine the bottle momentarily at lineal locations, while the bottle moves past in front of the detector as moved by the conveyor, so that the lineal examined locations provide information at least on the shape of the neck of the bottle and upper part thereof. The detector is mainly constituted by photo-diodes disposed in a row. The conveyor is disposed to transport the bottle between the illuminating means and the detector, so that the detector will examine the bottle from behind, referring to the illuminating means, and will supply information on the shape of the bottle on the basis of the shadow thrown by the bottle.
This particular solution in the prior art is based on examining the bottle that has been turned in, at discrete moments and at lineal locations, while the bottle is moving past the detector. As the bottle moves, the lineal examining location will thereby sweep over the entire bottle and a line image of the bottle will be obtained over the entire body. To perform this examination, a lineal camera may be advantageously used, which is simple in construction and advantageous regarding cost. The line image, e.g. a signal sequence of electrical pulses delivered by the lineal camera, is extremely appropriate for processing the image and shape of a bottle with a view to identifying accepted bottle shapes and recording accepted bottles.
If desired, for instance in conjunction with the lineal camera, the bottle may be illuminated with any illuminating means or lamp known in the art. If desired, it is possible to use, e.g. photodiodes arranged in a row instead of a lineal camera, in which case the bottle is appropriately illuminated from the opposite side, e.g. with the aid of light-emitting diodes, for instance with infra-red LED's arranged in a row. In that case, the examination may be timed to take place at given time intervals as the bottle is moving past between the illuminating means and the light diodes, in order to obtain a line image of the respective bottle under examination.
The detector and receiver means are placed directly opposite one another in the design disclosed in Finnish Patent No. 71892. The detector has the design of a lineal semi-conductor camera comprising a camera element and optics. Since the camera and the illuminating means are opposed, the mechanical dimensions of the means impose certain requirements on the optics of the camera, i.e. wide-angle optics are required. This has the consequence that in this solution of the prior art, a powerful parallax error is incurred. In other words, even minor displacement of the bottle on the line connecting the detector and the illuminating means, causes a considerable error in the result of measurement attained from a bottle on the conveyor.
In the solution disclosed in Finnish Patent No. 71892, the position of the bottle on the conveyor must be exactly correct, in which case the height is h.sub.1. If the position of the bottle is incorrect, then the height of the bottle will then be h.sub.2. The positional error .DELTA.s of the bottle on the conveyor causes error in height .DELTA.h=h.sub.2 -h.sub.1. On the strength of the foregoing, the accuracy requirements of this measuring system of the prior art are exceedingly high.